1. Field of the Invention
The present invention relates to a light-emitting module.
2. Related Background Art
In general, a light-emitting module comprises a semiconductor light-emitting device such as a semiconductor laser, and a housing for accommodating this light-emitting device. The housing has a plurality of lead terminals. By way of these lead terminals, the light-emitting device receives driving signals from the outside of the light-emitting module.
It is an object of the present invention to provide a light-emitting module for increasing the transmission rate of optical communications.
The inventor has been studying light-emitting modules which can achieve a transmission rate of 10 Gbps or higher. The inventor has found that, for achieving a transmission rate of about 10 Gbps, not only the operating speed of a driving device itself is critical, but also it is important that high-speed modulated signals from the driving device be transmitted to the semiconductor light-emitting device with a small deterioration. Based on this finding, the inventor has come up with the idea of accommodating not only a light-emitting device but also a driving device within a package, and implementing the light-emitting device and driving device close to each other on the same substrate.
When a semiconductor light-emitting device and a driving device are implemented on the same substrate, however, the temperature of the light-emitting device rises 10xc2x0 C. or more due to the heating of the driving device. This is because of the fact that the driving device consumes a power as high as about 1 W. When the temperature of the light-emitting device changes greatly, the power and oscillating wavelength of the light-emitting device fluctuates. This makes the output characteristic of the light-emitting module unstable.
For stabilizing the temperature of a light-emitting device, a substrate implemented with the light-emitting device may be mounted on a Peltier device. When implementing a driving device and a light-emitting device on the same substrate, it is necessary for the Peltier device to absorb the heat of both the driving and light-emitting devices and control the temperature. To this aim, a large Peltier module with a heat-absorbing capacity of about 1.5 to 2 W is required. This causes the light-emitting module to increase its size.
The light-emitting module in accordance with the present invention comprises a semiconductor light-emitting device; a first mounting member for mounting the light-emitting device; a driving device for driving the light-emitting device; a second mounting member for mounting the driving device; and a housing for accommodating the light-emitting device, first mounting member, driving device, and second mounting member. The first and second mounting members are disposed apart from each other within the housing.
Since not only a light-emitting device but also a driving device is accommodated within a housing, the distance between the light-emitting device and the driving device can be made shorter. In particular, when the first and second mounting members are disposed close to each other, the wiring length can be sufficiently short. As a result, driving signals modulated at a high rate can be transmitted from the driving device to the light-emitting device with a small deterioration. Therefore, the light-emitting module in accordance with the present invention can be used favorably as a light source for high-speed optical communications. Since the first and second mounting members are not directly in contact with each other, the heat generated by the driving device is hard to transmit to the light-emitting device. Hence, the light-emitting device is restrained from changing its temperature, and stabilizes its output.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.